From 81e7ef8ffc106945c5f7d21d3091b5a96c20f424 Mon Sep 17 00:00:00 2001
From: Hritik Raj <hritik23154049@akgec.ac.in>
Date: Sat, 24 Jan 2026 00:54:10 +0530
Subject: [PATCH] Add unit tests for FixedBitSet (Fixes #595)

---
 .../nasa/jpf/test/util/FixedBitSetTest.java   | 86 +++++++++++++++++++
 1 file changed, 86 insertions(+)
 create mode 100644 src/tests/gov/nasa/jpf/test/util/FixedBitSetTest.java

diff --git a/src/tests/gov/nasa/jpf/test/util/FixedBitSetTest.java b/src/tests/gov/nasa/jpf/test/util/FixedBitSetTest.java
new file mode 100644
index 00000000..706849f2
--- /dev/null
+++ b/src/tests/gov/nasa/jpf/test/util/FixedBitSetTest.java
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2014, United States Government, as represented by the
+ * Administrator of the National Aeronautics and Space Administration.
+ * All rights reserved.
+ *
+ * The Java Pathfinder core (jpf-core) platform is licensed under the
+ * Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ * * http://www.apache.org/licenses/LICENSE-2.0. 
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package gov.nasa.jpf.test.util;
+
+import gov.nasa.jpf.util.BitSet64;
+import gov.nasa.jpf.util.FixedBitSet;
+import gov.nasa.jpf.util.test.TestJPF;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+/**
+ * Unit tests for gov.nasa.jpf.util.FixedBitSet (using BitSet64 implementation)
+ */
+public class FixedBitSetTest extends TestJPF {
+
+  @Test
+  public void testBasicSetGet() {
+    FixedBitSet set = new BitSet64();
+    for (int i = 0; i < 64; i++) {
+      assertFalse("New set should be empty at " + i, set.get(i));
+    }
+
+    set.set(0);
+    set.set(10);
+    set.set(63);
+
+    assertTrue(set.get(0));
+    assertTrue(set.get(10));
+    assertTrue(set.get(63));
+
+    assertFalse(set.get(1));
+    assertFalse(set.get(62));
+  }
+
+  @Test
+  public void testClear() {
+    FixedBitSet set = new BitSet64();
+    
+    set.set(42);
+    assertTrue(set.get(42));
+    
+    set.clear(42);
+    assertFalse("Bit should be false after clear", set.get(42));
+  }
+
+  @Test
+  public void testCardinality() {
+    FixedBitSet set = new BitSet64();
+    
+    assertEquals("Empty set should have 0 cardinality", 0, set.cardinality());
+    
+    set.set(1);
+    set.set(5);
+    set.set(60);
+    
+    assertEquals("Should count set bits correctly", 3, set.cardinality());
+    
+    set.clear(5);
+    assertEquals("Should decrease count after clear", 2, set.cardinality());
+  }
+
+  @Test
+  public void testToString() {
+    FixedBitSet set = new BitSet64();
+    set.set(1);
+    set.set(3);
+    
+    String s = set.toString();
+    assertTrue("String representation should contain index 1", s.contains("1"));
+    assertTrue("String representation should contain index 3", s.contains("3"));
+  }
+}